Coordination Polymer and Monomer with the Cd(NO3)2Fragment Containing 2-Amino-5-Bromopyridine: Synthesis, Structures, NMR Study, and Luminescence Properties

The reactions of Cd(NO3)(2) center dot 4H(2)O with 2-amino-5-bromopyridine (.bp) afford compounds [Cd(NO3)(2)(Abp)(H2O)](n) (I) and [Cd(NO3)(2)(Abp)(2)(H2O)(2)] (II). The structures of both complexes are determined by single-crystal X-ray structure analysis (CIF files CCDC nos. 1938624 (I) and 1959680 (II)). Compound I is a coordination 1D polymer in which two chelate-bonded NO3- groups act as bridges. The coordination polyhedron of the octacoordinated central cadmium atom in compound I consists of seven oxygen atoms (one oxygen atom of water and six atoms of the NO3- groups) and one nitrogen atom of Abp, being a triangular dodecahedron. Complex II is a mononuclear molecule in which the octahedral coordination polyhedron of Cd is formed by four oxygen atoms of two water molecules and two NO3- groups and two oxygen atoms of two molecules of the Abp cycle. In both complexes, the amino group of Abp is not involved in coordination with the metal. Compound I is studied by H-1, C-31, and N-15 NMR spectroscopy of a solution of the polymer complex in CD3CN, and the most substantial difference in the chemical shifts of the bound and free Abp ligands is observed in the N-15 NMR spectra (37 ppm). According to the data of luminescence spectroscopy, compounds I and II exhibit an emission in a range of 430-690 nm.